Wednesday, July 23, 2014

Dandelions - mistakes in the field

Dandelions are ubiquitous plants, common in fields and gardens, and also both beloved and hated.  We love their fluffy fruiting heads with their wind-blown small parachute seeds.  It is probably one of the most well-known plants in society (except for some common ones that we grow on purpose).

However, not only dandelions have these types of fruits, and some of the popular photos of dandelions are actually other species. The most common mix-up is with Tragopogon species, goat beards. Both are members of the sunflower family, the Asteraceae.  How do you tell them apart?
Dandelion (Taraxacum)
from Lindman's flora, public domain.

The common dandelion (Taraxacum officinale) has:
  • yellow flowers (each head have many tiny, tiny flowers)
  • leaves that are lobed with large teeth
  • leaves in a rosette near the ground, no leaves on the flower stalk
  • fruiting heads about 3-5 cm in diameter (up to 2 inches)
  • the green bracts under the flowering  head are relatively short, and they barely just reach the full radius of the fruiting head.
  • there are more seeds in each head

Note the difference in the leaves and bracts to the leaves of goat's beard.

In the sunflower family, each seed is also a fruit.  So a sunflower seed is a little 1-seeded nut.

Goatbeards (Tragopogon sp. ) have:
Goatsbeard (Tragopogon),
from Thomé (1885), public domain
  • yellow or purple flowers (each head have many tiny, tiny flowers)
  • leaves that do not have lobes, and are very long and narrow ending in a long sharp point
  • leaves are present on the flower stalk
  • fruiting heads usually over 5 cm (over 2 inches)
  • the green bracts under the flowering  head are long, reaching beyond the full radius of the expanded fruiting head
  • you can blow these seeds away too
  • Other names for these plants are salsify and goat's beard. 

Below are some examples of stock photos that are sold as dandelion photos but actually are other species. Most photos marked as dandelions are correct, but a few are not. If you spend $40 and upwards on stock photos, I think you should assume you get the right species, don't you?
istockphoto for sale by user sunnybeach, marked as dandelion but showing goatsbeard.
Note the two long bracts hanging down from the fruiting head near the stem.
(Screenshot by, istockphoto image # 171660950.)
Another stockphoto, this time from Getty images, also showing goatsbeard (note long narrow and non-dented leaves). (Screenshot by, gettyimages photo # 128072731)
More examples on this Pinterest board: 'Dandelions' that are not real dandelions.